Ventilation and respiration – is essential to maintaining homeostasis. Ventilation is the act of moving air into and out of the lungs. Respiration is the exchange of gases – oxygen and carbon dioxide – between the alveoli and bloodstream. The process of gas exchange is called diffusion.

What causes us to breathe? The respiratory rate is regulated primarily by the autonomic nervous system that constantly monitors carbon dioxide levels in the blood. Increased levels of this cellular waste product cause the autonomic nervous system to stimulate an increase in the respiratory rate and volume to offload the excess CO2.

A second, back-up system exists which does not depend upon carbon dioxide levels in the bloodstream, but oxygen levels instead. This is called the hypoxic drive. For this type of patient, (typically a patient with chronic obstructive pulmonary disease or COPD), a decrease of oxygen in the bloodstream will stimulate breathing. Conversely, an increase in oxygen levels will cause the respiratory rate to slow. High volume oxygen delivery to a COPD patient who depends upon his hypoxic drive to stimulate breathing will eventually cause him to stop breathing. However, all patients in respiratory distress need high flow oxygen immediately regardless of their medical history.

How do we know a patient is breathing adequately?The EMT must evaluate respiratory rate, rhythm, and quality.

Age

Normal Respiratory Rates/Min

Adults

12 - 20 breaths/min

Children

15 - 30 breaths/min

Infants

25 - 50 breaths/min

Rate: The range of normal respiratory rates for an adult is 12 to 20 breaths per minute (BPM). Children breathe at 15 to 30 times a minute. The newborn can even have a rate of up to 60 BPM.To determine respiratory rate, the EMT counts the rise and fall of the patient’s chest for thirty seconds and then multiplies by two. (Remember that the patient may become self-conscious and alter his breathing rate if he knows you are watching.) For a patient in distress, respirations less than ten per minute or greater than 24 per minute need to be supplemented with high flow oxygen. The EMT can also ventilate the patient with a positive pressure device to provide artificial respiration. (Positive pressure devices include pocket masks and bag-valve-masks or BVM.)

Assessing a patient’s respiratory rate is often overlooked by EMTs. But it is essential information for the emergency department physicians especially if the patient is in respiratory distress. EMTs should assess and report a respiratory rate on every patient; make no exceptions!

Rhythm: Rhythm refers to the tempo of breathing. This is assessed noting the time from the peak of one chest rise to the next. If consistent, the rhythm is considered “regular.” When you’re awake, that rhythm can be affected by mood, exercise, and speech. When you sleep, the rhythm is more regular and even.

Irregular breathing patterns may also be caused by chronic illnesses (such as emphysema or asthma), fever, medication overdose, chest injuries, and hyperventilation. At the time of death, breathing patterns change. Breathing may simply stop, or slow down and become extremely shallow and then stop, or there can be a short series of great heaving gasps before the patient stops breathing entirely. The final respiratory effort is called agonal breathing.

A traumatic brain injury with increased intracranial pressure can alter the regularity of breathing.

An irregular breathing pattern is caused by many conditions. For example, a traumatic brain injury with increased intracranial pressure can alter the regularity of breathing. As the pressure within the skull increases, the patient’s breathing becomes more erratic with periods of deep, rapid breathing followed by slow, shallow breathing, followed by periods of apnea (absence of breathing). This pattern is called Cheyne Stokes breathing and requires aggressive management of the patient’s ventilations by the EMT.

Irregular breathing patterns may also be caused by chronic illnesses (such as emphysema or asthma), fever, medication overdose, chest injuries, and hyperventilation. At the time of death, breathing patterns change. Breathing may simply stop, or slow down and become extremely shallow and then stop, or there can be a short series of great heaving gasps before the patient stops breathing entirely. The final respiratory effort is called agonal breathingWhen breathing is inadequate, how does the brain compensate in an effort to maintain its equilibrium or homeostasis?

Initially it raises the body’s respiratory rate and volume (amount) of air inhaled or exhaled. If the rate increases to over 30 BPM, however, the volume of air being inhaled decreases to the point where the total overall volume is inadequate. Abnormal rapid breathing is called tachypnea; the patient is breathing too rapidly to adequately refill the alveoli.

Once the body’s compensatory mechanism ceases to function, the respiratory rate and volume both decrease. Suddenly the patient is breathing at ten BPM or less. (Abnormal slow breathing = bradypnea) The volume inhaled decreases and total overall volume becomes inadequate. The EMT should manage both conditions – tachypnea and bradypnea – by ventilating the patient with a bag-valve-mask device.

Quality: Here the EMT assesses how labored the patient’s breathing may be as well as any sounds that may be made during inhalation and exhalation. Quality falls into four categories: normal, shallow, labored or noisy.

Let’s first look at normal quality. A healthy person breathes with little effort. The diaphragm and the external intercostal muscles (those between the ribs) are the muscles primarily responsible for ventilation. No additional muscles of respiration (called accessory muscles) are used.

There is also a normal depth of respiration which gives rise to a steady rhythmic movement of the chest cage. However, the movement is minimal and can be almost imperceptible on a healthy, immobile patient. Finally, normal respirations make no noise; they are virtually silent.

EMTs must assess each patient’s respiratory effort by visual inspection (looking for equal chest rise and fall), auscultation (listening to the lungs with a stethoscope) and palpation (feeling for deformity or any other irregularity).

Shallow breathing occurs when there is only a slight movement of the chest or abdomen. We see this often in the nursing home patient who has been bedridden for some time. Ventilation is poor; not enough oxygen and carbon dioxide are being moved in and out of the lungs to allow for proper diffusion.

Labored breathing causes an increase in the amount of work that the body needs to do to exchange lung volume. The patient struggles to get air in and out. The EMT should be aware of signs of labored breathing:How is your patient positioned? Is he sitting upright, leaning forward on his hands in a tripod position? Is he unable to lie down? Does he sleep with several pillows under his head and upper body? All of these signs point to respiratory distress.

Do you see any accessory muscle usage when the patient breathes? Accessory muscles include those in the neck, clavicles, and abdomen. If the patient is breathing adequately, these muscles do not constrict. However, when respiration is inadequate, accessory muscles are used to increase the volume of air being moved. Severe respiratory distress causes these muscles to retract, creating depressions in the neck, above the shoulder blades, and between and below the ribs.

Does the pediatric patient present with nasal flaring? Are there sternal retractions, i.e., does the child’s sternum pull inward when he inhales? If so, the pediatric patient is in severe respiratory distress.

The EMT also evaluates breathing by listening to the patient speak. Does she have to interrupt the words in each sentence to take a breath? Is she gasping for air after a phrase or a few words? This is labored speech and is not normal.

Finally, is the patient’s breathing noisy? What do you hear without a stethoscope? Is there stridor, a high pitched sound on inspiration, or grunting on expiration? Is there an obstruction which is causing lack of sound altogether or a partial obstruction causing crowing or gurgling?What do you hear with a stethoscope? Breath sounds should be evaluated in three places both anteriorly and then posteriorly. Noisy breathing can further be described as:Rales, fine crackling sounds, indicate fluid in the lungs.Rhonchi, coarse sounds, indicate more significant fluid buildup or mucous accumulation.Wheezing, a high-pitched (usually expiratory) sound, indicates lower airway narrowing and is prevalent in asthma.No sound at all. If the respiratory sounds are not bilateral, the patient may have a pneumothorax or tension pneumothorax. The patient might also have had a lung removed.